ums(4) and Apple Mighty Mouse

["José M. Fandiño"]

Hello,

  I'm trying to use a Mighty mouse, but it doesn't seems
to work very well with FreeBSD 6.1RELEASE

when the mouse is attached, this message is printed in
the console:

ums0: Mitsumi Electric Apple Optical USB Mouse, rev 1.10/1.08, addr 2, iclass 3/1
ums0: 4 buttons and Z dir.

the 4 buttons detected are:

logical     physical
--------    ---------------------------
button 1 -> right button
button 2 -> trackball middle button
button 3 -> left button
button 4 -> simultaneously pressing
             right and left side buttons

this mouse has a trackball instead of a wheel, so
the wheel has horizontal and vertical scrolling.

Now is when the problem comes, the Z axis is mapped to
the horizontal scrolling, which is very confusing because
to scroll a web page you need move horizontally the
trackball.

it seems as if the ums driver were unable to generate events
for the vertical scrolling, this is that I get running moused
in debug mode (note the empty packet for up and down events):

# /usr/sbin/moused -p /dev/ums0 -d -f
moused: proto params: f8 80 00 00 8 00 ff
moused: port: /dev/ums0  interface: usb  type: sysmouse  model: generic
.
// horizontal event (right scrolling)
.
moused: received char 0x87
moused: received char 0x0
moused: received char 0x0
moused: received char 0x0
moused: received char 0x0
moused: received char 0x0
moused: received char 0x1
moused: received char 0x7f
moused: assembled full packet (len 8) 87,0,0,0,0,0,1,7f
moused: tv:  1155672704 308385
moused: flags:80000000 buttons:00000000 obuttons:00000000
moused: activity : buttons 0x00000000  dx 0  dy 0  dz 1
.
// horizontal event (left scrolling)
.
moused: received char 0x87
moused: received char 0x0
moused: received char 0x0
moused: received char 0x0
moused: received char 0x0
moused: received char 0xff
moused: received char 0x0
moused: received char 0x7f
moused: assembled full packet (len 8) 87,0,0,0,0,ff,0,7f
moused: tv:  1155672705 812598
moused: flags:80000000 buttons:00000000 obuttons:00000000
moused: activity : buttons 0x00000000  dx 0  dy 0  dz -1
.
// vertical event (up and down scrolling)
.
moused: received char 0x87
moused: received char 0x0
moused: received char 0x0
moused: received char 0x0
moused: received char 0x0
moused: received char 0x0
moused: received char 0x0
moused: received char 0x7f
moused: assembled full packet (len 8) 87,0,0,0,0,0,0,7f

is there any way to get events for the up and down trackball
movements?